RX-8 Exhaust

A cat-back, emissions legal exhaust system is one of the most popular upgrades for the RX-8.

The RX-8 Renesis engine is a remarkable combination of detail improvements that have been developed over many years.

The largest difference between this engine and all previous Mazda rotaries is the side exhaust porting. This style of porting has both positive and negative consequences. On a positive note, side exhaust porting opens slow, closes slow (relative to peripheral exhaust porting) and causes a substantial pressure drop in the free stream of exhaust where the flow has to make some awkward turns out of the combustion chamber. The reason this is "positive" is that it softens the exhaust pulses and cools the exhaust. This means that exhaust gas temperatures drop from 1800°F and more with peripheral exhaust ports to roughly 1600° F now. Thus, the catalytic converter and exhaust can be made of less expensive materials and the muffler can be less restrictive while still offering a "streetable" exhaust note. The "negative" side is the that removing the muffler, or the catalytic converter, provides very little power gain! The main restriction is still there - the exhaust ports. This causes the engine to be insensitive to exhaust tuning - the pulses are less sharp and the return path is less direct to the chamber.

We still have hope that continued research in exhaust porting may provide performance improvements, but there are very serious restrictions to the shape of the port profiles caused by the way the side corner seals move across the ports.

Utilizing our in-house dyno test facilities, Racing Beat’s design team spent considerable effort to fine-tune the internal canister design of our muffler canister to provide what we believe is the ultimate rotary exhaust note! During development of the exhaust, we worked extensively to find the optimum balance between power and sound level. Too much sound dampening would rob power; too little dampening would bring the exhaust note up to unacceptable levels.

Just what is "unacceptable"? We assumed that an individual that has purchased a RX-8 is seeking an exhaust note that reflects the character of both the car and the maturity of the car owner. The exhaust note that we envision for this car should provide a modest sound level increase over stock, but any harsh or "tinny" tones should be suppressed. Cruising speeds should not produce any droning or buzzing tones, but provide a deep melodic tone that doesn’t distract from the driving experience. But, jump on the throttle and the exhaust should come alive with an aggressive note that enhances the driving experience. Refined and modest while cruising; aggressive and authoritative under acceleration - that is the balance that we strived to achieve!

The Racing Beat Race Exhaust System for the RX-8 is designed to offer a substantial weight savings over the stock exhaust system and conform to a 92 decibel sound level limit.* The single outlet tip is angled downward to further deflect the exhaust note. (The exhaust outlet does not extend through the opening in the rear bumper.) As compared to the stock system (39 lbs), the RB Race System (26 lbs) offers a 13 lb. weight reduction. Although the sound output is notably louder than the stock system, particularly under full throttle, this system can be used for daily "street" driving for those that desire an exhaust that produces a louder, more exotic and aggressive exhaust note.

Racing Beat also offers a full 304-stainless steel catalytic converter replacement pipe for RX-8 racing applications. This mandrel-bent 3" OD racing pipe is a direct bolt-on replacement for the stock catalytic converter section. This pipe utilizes a genuine OEM rear mounting flange for a secure fit to the stock (or an aftermarket) exhaust system. The race pipe is equipped with a sensor fitting for the oxygen sensor. (Note: Placement of the sensor in the pipe will cause the "check engine" light to be illuminated, but performance and engine systems will not be affected.)